Piston



' April 28, 1936';

A. L. NELSON PISTON 3 Sheets-Sheet 1 Filed May 27, 1929 4 hventoz: Z

35 mime l;

April 28, 19 36. r x NELSON 2,038,754

PISTON Filed May 27; I923 s Sheets-Sheet 2 F a-Z;

April 28, 1936. v A. L. NELSON PISTON Filed May 27, 1929 a Sheets-Sheets avwentoz Q 351;, 14 WW a Patented Apr. 28, 1936 UNITED STATES PATENTOFF-ICE PISTON Adolph L. Nelson, Detroit, Mich.

Application May 27, 1929, Serial No. 366,237

Claims.

This invention relates to pistons for internal combustion engines, andparticularly to such pistons for use in motor vehicles.

A particular object of the invention is to provide 5 a piston that maybe formed of a light-weight material, such as an alloy of aluminum, inwhich each bearing face is braced on each side by a lateral tieextending from the bearing face to a part of the piston pin boss. Thepart of each pin 0 boss to which all or some of the ties are attachedmay be separated either partially or entirely from the remainder of thepin boss.

The invention is carried out by properly placing a spacing disc on eachof the core pins thatare inserted in the mold to form the openingsthrough the piston pin bosses. The piston metal is then poured in theusual way, and in the resulting piston the discs divide the bosses. Byvarying the shape of the disc and the adjacent piston parts it ispossible to have the pin bosses either completely or only partiallyseparated by the discs.

While preferred forms of the invention have been disclosed for purposesof illustration, it should be understood that various changes may bemade in the structure or arrangement of parts Without departing from thespirit and scope of the invention as hereinafter set forth and claimed.

In the drawings: Fig. 1 is a side elevation of a piston embodying theinvention.

Fig. 2 is an elevation, partly in section, taken at right angles toFig. 1. v

Fig. 3 is a bottom plan view of the piston. Fig. 4 is a section taken online 4-4 of Fig. 2. Fig. 5 is a. vertical section showing a modified ormof the invention.

Fig. 6 is an elevation, partly in section, of a further modification.

Fig. 7 is a partial vertical section of a different arrangement of theparts.

Fig. 8 is a plan view of the Washer used in the piston of Fig. 7.

Fig. 9 is a view similar to Fig. 7 but showing a still differentmodification. Fig. 10 is a section on line |0I0 of Fig. 9. V

Fig. 11 is a vertical section of another species. Fig. 12 is a sectionon line l2l2 of Fig. 11. Fig. 13. is a plan view of a modified washer.Referring to Figs. 1 to 4 more particularly, the reference character It!indicates the head of. the piston, and character H is applied to thepiers which depend from the head and carry the piston pin bosses I2. Thepiston skirt includes a lower circular part l3 and cylinder-bearingportions I4 and 15. A tie it extends downwardly from each portion 15.These parts are formed of a suitable metal, such as an alloy ofaluminum. 5 Each piston pin boss is divided into two parts, an outerpart I9 and an inner part 20, by discs 2|. These discs may be of anymaterial suitable for the purpose, but the preferred material is copper.

These discs are properly positioned on the core 10 pins that form theholes through the piston pin bosses, before the pins are inserted in themold. The piston metal is then poured into the mold and after coolingthe rough casting is removed from the mold in the usual manner. 15

In the piston illustrated in Figs. 1 to 4 the discs 2| are of such asize and shape that they completely divide the main body of each pinboss into two separate parts I9 and 20. It will be observed however,that these parts l9 and 20 are connected 20 to each other through thematerial of the reinforcing rib 22 which is homogeneous with the pier II.

In the modification illustrated in Fig. 6 the arrangement of parts issimilar to that of the form of Fig. 2 except that the ribs 22 are notpresent, and therefore the discs 2| completely separate the parts l9 and20 of the pin bosses.

The species .of Fig. 5 embodies discs that are 30 elongated at the top,and the ribs 22 are widened where they envelope the upper edges of thediscs.

In this case the parts 19 and 20 of the pin bosses are united abovethrough the material of the rib 22, but the split between the parts [9and 20 ex- 35 tends farther away from the axis of the pin boss. Theheight of the upward extension on the disc can be varied to give anydesired degree of flexibility between the two par-ts of the pin boss.

In the modification of Figs. 7 and 8 the disc 40 24 is formed with anotch 25, which is positioned in the mold in such a way that the pistonmaterial forms a tie on the lower side of the piston pin boss connectingthe parts [9 and 20.

Figs. 9 and 10 also'show the tie at the lower side of the pin boss, buthere a completely round disc is used, and the tie 26 extends below thedisc. No special care in positioning is required with this form. 50

In Figs 11 and 12 the ties 21 are formed at one of the lateral sides ofeach boss. The figures also show the disc formed with a circularcorrugation 28, which serves keep the disc in true shape for ease inhandli g, and also holds the 55 disc firmly in place after the pistonmetal has been cast around it.

The pressed corrugation may be given an irregular form, as shown as 29in Fig. 13, to further prevent movement of the disc.

A slot may be formed in one of the thrus faces, as indicated at 30. Thethrust faces may also be relieved at their lateral edges. The relievedarea may increase toward the upper edges of the thrust faces, such aform of relief being shown at 3| in Figs. 1 to 4. No relief is requiredwhere the bosses are completely divided as in Fig. 6. g

The use of discs as disclosed herein serves the same purpose as slotssimilarly disposed in the bosses, but the present means and methodpresents a. more eflicient and practical way of dividing the bosses thaneither using thin cores to cast the piston with the slots, or machiningthe slots after the pistons are cast.

It should be noted that this invention relates particularly to themethod of dividing the pin bosses, and obviously the piston skirt can bemade of any suitable form, may be sloted wherever desired, and may besupported from the piston pin bosses in any preferred manner.

By thus dividing the boss there is permitted a certain amount offlexibility and yielding between the two parts of the boss, the amountand character of the flexibility depending on the location and extent ofthe slot formed by the disc.

The discs also act as heat insulation between the two parts of eachboss. This is true even where the discs are of. copper, as the hotpiston metal when cast around the discs causes oxidation of the surfacesof the copper discs, and the piston metal therefore cannot lie closeenough to these surfaces to form a joint having good heat transferringproperties. As an added precaution it is possible to give the discs apreliminary coating to further insure a heat-insulating joint betweenthe piston metal and the discs. It is also contemplated that the discsmay be formed of a heat-insulating material such as high nickel steel.

The use o1 thin copper discs is particularly advantageous, as any pistoncastings that are imperfect can be re-melted without removing the discs,the slight percentage of additional copper being unimportant.

The discs can be formed with irregularities thatwill help to anchor themin place, or the discs may be intended for removal after the casting ismade and may be formed with ears to facilitate such removal.

I claim:

1. A piston including a head and piston pin bosses, a spacing disclocated in each pin boss, the spacing disc separating the boss intoinner and outer parts, and a homogeneous tie connecting the inner andouter parts of the boss, the homogeneous tie being located at a. lateralside of the pin boss.

2. A piston comprising ahead, piers depending from the head, piston pinbosses formed in the piers, cylinder-bearing portions located onopposite sides of the piston, the upper ends of the cylinder-bearingportions being separated from the head and from the piers, tiesconnecting the cylinder-bearing portions to the piers, the head, piers,ties and cylinder-bearing portions forming a homogeneous mass oflight-weight material, a spacing disc'located in each pin boss andserving to separate the boss intoinner and outer parts, said inner andouter boss parts being completely separate from each other except forties connecting them together at one side of the boss only.

3. A piston comprising a head, piers depending from the head, piston pinbosses formed in outer parts, said inner and outer boss parts beingcompletely separate from each other except for ties connecting themtogether at a lateral side of the boss only.

4. A piston comprising a head, piers depending from the head, piston pinbosses formed in the piers, cylinder-bearing portions located onopposite sides of the piston, the upper ends of the cylinder-bearingportions being separated from the head and from the piers, tiesconnecting the cylinder-bearing portions to the piers, the head, piers,ties and cylinder-bearing portions forming a homogeneous mass oflightweight material, a spacing disc locatedin each pin boss and servingto separate the boss into inner and outer parts, said inner and outerboss parts being completely separate from each other except for tiesconnecting them together at the lower side of the boss only.

5. A piston comprising a head, piers depending from the head, piston pinbosses formed in the piers, cylinder-bearing portions located onopposite sides of the piston, the upper ends of the cylinder-bearingportions being separated from the head and from the piers, tiesconnecting the cylinder-bearing. portions to'the piers, the head, piers,ties and cylinder-bearing pertions forming a homogeneous mass oflightweight material, a spacing disc located in each pin boss andserving to separate the boss into inner and outer parts, said inner andouter boss parts being completely separate from each other except forties connecting them together at a point above the axis of the bossonly.

ADOLPH L. NELSON.

